Allow fixed-height minibuffer, bind resize-mini-windows appropriately

[clemera]

When there are less actual candidates than selectrum-num-candidates-displayed specifies the minibuffer pops up at a lesser height than usual. I think that is annoying because my eyes are used to see the prompt at a higher position. I would like to be able to always give it the same height regardless how many candidates are available. This could be by default or by adding a user option, what do you think?

[clemera]

I just stumbled across a related problem: The variable resize-mini-windows controls how minibuffer should resize, when set to nil selectrum is not able to show its candidates at all so it should probably be let bound to grow-only.

[raxod502]

I would like to be able to always give it the same height regardless how many candidates are available.

Yep, sounds reasonable. It should be a new user option, disabled by default.

it should probably be let bound to grow-only

Also true. I didn't know about this variable before, thanks for pointing it out.

[raxod502]

Let me know what you think.

[clemera]

Looks good to me, alternatively we could check for window-height and use enlarge-window but I guess there is no problem to insert empty lines.

[raxod502]

I like this solution as it means there's only one way that we set the window height, which is by inserting text. Thanks.